Air lock or thermostat?

decoupe

decoupe

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While I sit at the side of the road waiting for the engine to cool off I thought I would ask - are the symptoms of an air lock or a thermostat failing to open the same? The hose from the bottom of the rad is cold so no water moving through it. Opened the air bleed for 5 seconds and just got antifreeze. Thermostat is correct (as per sfdon's recommendations) and all parts new including an aluminum triple core rad.

I'm guessing it's the thermostat. And it's starting to rain.
 
Do you have any extra coolant lines? If so, remove the line from the expansion tank, and hold it up as high as you can. Put a second piece of coolant line into the expansion tank, and blow into it slowly until fluid comes out of the small line from the radiator that you're holding up high. Once that happens, your cooling system doesn't have air in it.

If the lower hose is dead cold, and the upper hose is super hot, you might not be flowing through the radiator, which sounds like a t-stat.

I just went through all of this a few weeks ago, with a roadside call to Don. Thankfully my woes were a bad ground; cleaning up a few grounds and replacing the temp sensor got me back on the road.
 
The car is back in our shop and cooling off. Thanks for the tip on purging air from the cooling system - I'll pull the thermo and test it first.
 
You need to post a pic of your Tstat and a pic of the housing
That it goes in. NOT the cover but the housing.
You need to disco the small hose at the top of radiator and start the
Car to check for steady stream of fluid, then blow into hose to verify not blocked into
Expansion tank.
 
Do you see a date or an embossed letter "A" on the housing?
(Not the cover)
 
Don,

The housing (fourth photo link) has the letter A on it - hard to see through the powder coat. I'm going to use another (almost zero mileage) T-stat I have, button it up and fire it up. Should work.

Restart - not all are metric let alone BMW.


http://i54.photobucket.com/albums/g120/decoupe/photo3_zpsbbaf0357.jpg
http://i54.photobucket.com/albums/g120/decoupe/photo5_zps670fde6c.jpg
http://i54.photobucket.com/albums/g120/decoupe/photo5_zps670fde6c.jpg
http://i54.photobucket.com/albums/g120/decoupe/photo4_zps35c83bed.jpg
http://i54.photobucket.com/albums/g120/decoupe/photo_zps68399fd8.jpg
 
Slow down.......
The housing with the "A" requires a different tsat than the early housing.
1153171304071

Early and late parts do NOT interchange.
You will either overheat or never warm up depending on the combination.
One never opens and never closes.

With a "A" you must use 1153171304071
 
The T-stat I just pulled (that wasn't opening) was a 11531713040. So was it just defective?

Sorry about all the questions.
 
Did you drill it ?
Sorry about the extra numbers.....

11531713040 is it.
 
Yes I drilled it. Removal of the T-stat from the housing was difficult - came out in two pieces with the round collar needing substantial leverage before it popped out.

My options are
i) buy/install another 11531713040.
ii) install the older one that 11531713040 replaced.
iii) run without a T-stat and worry about it when I pull the car off the road for the winter.

In the first two options I at least know I have to check that coolant is running through the rad before driving the first time.

Thanks Don
 
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do not run without a t-stat. the car will need longer to warm up even in summer and the wear on the engine will be increased.

T-Stats are a dime a dozen. Go get a fresh one from BMW and be done with it. Automotive 101 should not give a headache.
 
Our friend is right..
Got to have it.
Don't run a early version tstat in a late housing.
Get another xxxxx040 , drill it and jack the front of the car up when you install it.
That tilt makes pretty it pretty easy to install.
 
Autohausaz name brand......

11531713040
Behr - Thermostat; 80 Degree C; Without Gasket
1 per car. Also need 035121119 seal.
$22.20
SALE$23.13
List: $37.00
 
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